Archaeologists in Sweden have found two long rows of wooden post holes at nearly right angles to each other. One of the rows is a kilometre long and consists of 144 post holes. The other extends at least 500 metres. The holes are spaced every six metres and the rows are 500 metres apart.

“We think the wooden poles were high, perhaps over eight to ten metres. They have been easily spotted from a distance,” says the project leader of the dig, Lena Beronius-Jörpeland, an archaeologist with the Swedish National Heritage Board.